Now You Know Dyeing Cotton Knit Goods without Bleaching (Part-2)

Scope of Dyeing Cotton Knit Goods without Bleaching Operation for Energy Saving and Cost Reduction (Part-2)

Md. Palash Hossain
Department of Textile Engineering
Dhaka University of Engineering & Technology (DUET)
Email: palashsakal@yahoo.com

Previous Part

2.2 Methods:
Method followed: Exhaust Method

2.2.1 PROCESSES FOLLOWED IN LABORATORY TRIAL:

A. Pretreatment:

Table 6: Recipe for pretreatment

With Bleaching		Without Bleaching
Name of chemicals	Quantity (g/l)	Name of chemicals	Quantity (g/l)
Wetting agent	1.5	Wetting agent	1.5
Sequestering agent	1.5	Sequestering agent	1.5
Caustic soda (NaOH)	5	Caustic soda (NaOH)	5
Hydrogen peroxide(H₂O₂)	5	-	-
Stabilizer	1.5	-	-
Peroxide killer	0.05	-	-
M:L	1:10	M:L	1:10
Temperature	100^oc	Temperature	100^oc

Sequence followed in scouring & bleaching:

Figure-1: Scouring and bleaching procedure scheme in IR lab dyeing machine

Sequence followed in scouring without bleaching:

Figure-2: Scouring without bleaching procedure scheme in IR lab dyeing machine

Working procedure:
All the chemicals were taken according to recipe. 10% stock solution of caustic soda was prepared. Then the samples were given in scouring bath. The program was set for 40 min at 1050c. After unloading of the samples normal wash were done for 5 minutes. Then peroxide killer was used in conventional way for removing H2O2 from the fabric at 800c for 15-20 min. After that acid wash was done for the both samples for 10 min. Then hot wash was performed with detergent for 10 min at 800c. Finally cold wash was done.

Figure-3: Infra Red lab dyeing machine

A. Dyeing:
Table 7: Recipe for lab dyeing (0.5% shade)

With peroxide treated fabric		Without peroxide treated fabric
Name of chemicals	Amount(g/l)	Name of chemicals	Amount(g/l)
Leveling agent	1.5	Leveling agent	1.5
Wetting agent	1.5	Wetting agent	1.5
G. Salt	25	G. Salt	25
Soda ash	8	Soda ash	8
Detergent	1	Detergent	1

Working procedure:

Stock solution preparation: During the lab dip, little amount of dyes and other chemicals were required. 1 gm of dye has been taken in 100 ml of warm water and was made as 1% stock solution of dye. Similarly 20% of Na2CO3 (Sodium carbonate) and 20% of Gluber salt solution have been prepared. The formulae below was exercised to get the accurate amount of dyes and chemicals

Sample preparation: The pretreated fabric had been cut and made sample of 5 gm by electronic balance. The sample size was required as rectangular to assess rubbing fastness test. Then all the samples ware soaked in distilled water for few minutes and squeezed well which then got ready for dyeing.

Dyeing : All the auxiliaries, salt and dyes were placed in dye bath from stock solution and water was taken to maintain 1:10 liquor ratio. Then fabric was added in dye bath at room temperature and run for 5 minute. Temperature was gradually increased (2o/min) up to 60oC. At this temperature the system was run for 15 min and soda dosing was performed for 45 min. After Completing dyeing the dye liquor was drained out.

After treatment: Normal wash was done. Then hot wash was performed at 80oC with detergent for 10 min. Finally cold wash has been done for 5 min followed by drying at 100oc for 20 min.

Sequence followed in laboratory dyeing:

Figure- 4: Dyeing procedure scheme in IR lab dyeing machine

2.2.2 PROCESS FOLLOWED IN BULK TRIAL:

Specification of used machineries:

Machine name-MCS
Origin-Italy
Machine capacity-1500 kg
Maximum capacity for single jersey-1000 kg
Maximum Temperature 13000c
Maximum water capacity-11200 liter
No. of nozzle-06

A. Pretreatment:
Recipe for 1000 kg knitted (S/J) Fabric:
Table 8: Recipe of pretreatment process for bulk production

Working procedure:

Conventional process			Proposed process
Steps	Tem	Time	Steps	Tem	Time
Fabric loading		20 min	Fabric loading		20 min
Addition(detergent + seq. agent + anti creasing + stabilizer)	50⁰c	5min	Add (detergent + seq. agent )	50⁰c	3 min
Caustic dosing	50⁰c	5 min	Caustic dosing	50⁰c	5 min
Rising temperature and addition H₂O₂	70⁰c	10 min	Rising temperature	80⁰c	15 min
Rising temperature	98⁰c	15 min	Run time		30 min
Run time		60 min	Drain out + fill		5 min
Cooling	80⁰c	10 min	Hot wash	80⁰c	10 min
Drain out + fill		5min	Drain out + fill		5 min
Hot wash	80⁰c	10 min	Neutralization	60⁰c	15 min
Drain out + fill		5 min	Enzymes wash	55⁰c	60 min
Peroxide killer	90⁰c	10 min	Drain out + fill		5 min
Drain out + fill		5 min	Washing		10 min
Neutralization	60⁰c	15 min	Drain out + fill		5 min
Enzymes wash	55⁰c	60 min
Drain out + fill		5 min
Washing		10 min
Drain out + fill		5 min
Total time	255 min		Total time	188 min

A.Dyeing:
Recipe:
Table 9: Recipe for dyeing and after treatment

Conventional process			Proposed process
Name of dyes & chemicals	Brand name	g/l	Name of dyes & chemicals	Brand name	g/l
Leveling agent	Dekoven-LVR	1	Leveling agent	Dekoven-LVR	0.5
Anticr . agent	Rucolin-JES	1	Anticr . agent	Rucolin-JES	2
A.acid	Ruco Acid	1	A.acid	Ruco Acid	1
G.salt		30	A.acid	Ruco Acid	0.75
Yellow	Polafix Yellow 3RS	1.0%	Yellow	Polafix Yellow 3RS	1.0%
Red	Polafix Red 3BS	0.3%	Red	Polafix Red 3BS	0.3%
Black	Polafix Black B	0.7%	Black	Polafix Black B	0.72%
Soda		12	Soda		12
Soaping agent	Albatex-AD	0.5	Soaping agent	Albatex-AD	0.5
Fixing agent	Neofix-R250	0.5	Fixing agent	Neofix-R250	0.5
Softener	Sapamine-CWS	1	Softener	Sapamine-CWS	1

Working procedure:
Sequence followed in dying:

Conventional Process			Proposed process
Steps	Tem	Time (min)	Steps	Tem	Time (min)
Add leveling	50⁰c		Add leveling	50⁰c
Salt dosing	50⁰c	10	Salt dosing	50⁰c	10
Color dosing	50⁰c	15	Color dosing	50⁰c	15
Run time		10	Run time		10
Soda ash dosing	50⁰c	20	Soda ash dosing	50⁰c	20
Fixation	60⁰c	60	Fixation	60⁰c	60
Drain out + fill		5	Drain out + fill		5
Total time	120 min		Total time	120 min

Sequence followed in after treatment:

Conventional process			Proposed process
Steps	Tem	Time	Steps	Tem	Time
Normal wash		10	Normal wash		10
Drain out + fill		5	Drain out + fill		5
Hot wash(soaping)	80⁰c	10	Hot wash(soaping)	80⁰c	10
Drain out + fill		5	Drain out + fill		5
Normal wash		10	Normal wash		10
Drain out + fill		5	Drain out + fill		5
Neutralization		10	Neutralization		10
Drain out + fill		5	Drain out + fill		5
Fixing		10	Fixing		10
Drain out + fill		5	Drain out + fill		5
Softening		10	Softening		10
Drain out + fill		5	Drain out + fill		5
Unload		20	Unload		20
Total time	110		Total time	110

2.2.3 PROCESS FOLLOWED IN TESTING

A. Color fastness to wash
Method followed: ISO 105 C03

B. Color fastness to rubbing /crocking
Method followed: EN ISO 105×12

C. Color fastness to perspiration:
Method followed : ISO105E02

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